The present invention relates to an electric thrust reverser actuation system and, more particularly, to a system and method for sustaining electrical power during a momentary power interruption in an electric thrust reverser actuation system.
When jet-powered aircraft land, the landing gear brakes and imposed aerodynamic drag loads (e.g., flaps, spoilers, etc.) of the aircraft may not be sufficient to slow the aircraft down in the required amount of distance. Thus, jet engines on most aircraft include thrust reversers to enhance the stopping power of the aircraft. When deployed, thrust reversers redirect the rearward thrust of the jet engine to a forward direction, thus decelerating the aircraft. Because the jet thrust is directed forward, the aircraft will slow down upon landing.
Various thrust reverser designs exist in the art, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Thrust reverser designs used most prominently with turbofan jet engines fall into three general categories: (1) cascade-type thrust reversers; (2) target-type thrust reversers; and (3) pivot door thrust reversers. As will be discussed more fully below, each of these designs employs a different type of xe2x80x9cmoveable thrust reverser component,xe2x80x9d as that term is defined herein below.
Cascade-type thrust reversers are normally used on high-bypass ratio jet engines. This type of thrust reverser is located at the engine""s midsection and, when deployed, exposes and redirects air flow through a plurality of cascade vanes positioned on the outside of the engine. The moveable thrust reverser component in this design may include several translating sleeves or cowls (xe2x80x9ctranscowlsxe2x80x9d) that are deployed to expose the cascade vanes. Target-type reversers, also referred to as clamshell reversers, are typically used with low-bypass ratio jet engines. Target-type thrust reversers use two doors as the moveable thrust reverser component to block the entire jet thrust coming from the rear of the engine. These doors are mounted on the aft portion of the engine and form the rear part of the engine nacelle. Pivot door thrust reversers may utilize four doors on the engine nacelle as the moveable thrust reverser component. In the deployed position, these doors extend outwardly from the nacelle to redirect the jet thrust.
The primary use of thrust reversers is, as noted above, to enhance the stopping power of the aircraft, thereby shortening the stopping distance during landing. Hence, thrust reversers are primarily deployed during the landing process. More specifically, once the aircraft has touched down, the thrust reversers are deployed to assist in slowing the aircraft. Thereafter, when the thrust reversers are no longer needed, they are returned to their original, stowed position. In the stowed position, one or more stow seals prevent air from flowing through the transcowls or doors, depending on the thrust reverser design. Moreover, stow locks are engaged to prevent unintended deployment of the thrust reversers.
The movement of the moveable thrust reverser components in each of the above-described designs has, in the past, been accomplished via a hydraulic system. Such systems include hydraulic controllers and lines coupled to the aircraft""s hydraulic system, hydraulic actuators connected to the moveable components, and hydraulically controlled locking mechanisms. More recently, however, thrust reverser actuation is being controlled by electric (or electromechanical) systems. These systems include one or more electronic controller units that control the operation of one or more electric motors that are coupled to the moveable thrust reverser components via actuators. These systems further include one or more electrically operated locking mechanisms that are operable to lock the moveable components in the stowed position.
As with various other aircraft systems, electric thrust reverser actuation systems are required to withstand certain postulated events without incurring damage to the system. One such event is a postulated power interrupt event that occurs for a specified minimum time period. The specified minimum time period being the maximum design time period required for the system to switch from its primary power source to a secondary power source. Since the locking mechanisms are, for flight safety considerations, designed to be energize-to-release type of locks, if the postulated power interrupt event occurs the locks will be momentarily deenergized and attempt to engage. Thus, if the power interrupt event occurs during movement of the moveable thrust reverser components, potential damage to system components may result.
Hence, there is a need for a system and method for controlling the movement of one or more moveable thrust reverser components that solves one or more of the problems identified above. Namely, a system and method for sustaining electrical power during a postulated momentary power interruption event in an electric thrust reverser actuation system that avoids system damage by maintaining power to the electrically operated locking mechanisms during the power interruption.
The present invention provides a system and method for controlling an electric thrust reverser actuation system that avoids system damage during a postulated power interrupt event. Specifically, and by the way of example only, the electrical status of a power source that supplies electrical power to an electric motor used to move one or more moveable thrust reverser components is determined by a monitor circuit. The monitor circuit produces a status signal indicative of the power source""s electrical status, and a controller circuit, in response to the status signal, controls the electric motor to operate in either a motoring mode or a generating mode. When the electrical status of the power source is xe2x80x9cenergized,xe2x80x9d the controller circuit controls the electric motor to operate in the motoring mode. Conversely, when the electrical status is xe2x80x9cdeenergized,xe2x80x9d the controller circuit controls the electric motor to operate in the generating mode.
In one aspect of the present invention, a system for controlling the movement of a thrust reverser includes an electric motor, one or more actuators, a monitor circuit, and a controller circuit. The electric motor is coupled to receive electrical power from a power source via one or more supply lines for operating in a motoring mode. The one or more actuators are coupled to the electric motor and are operable to move the thrust reverser between a stowed position and a deployed position in response to rotation of the electric motor. The monitor circuit is coupled to the power source and is operable to produce a status signal indicative of an electrical status thereof. The controller circuit is coupled to receive the status signal from the monitor circuit and is operable, in response thereto, to control the electric motor to operate in a generating mode when the status signal indicates the power source is deenergized, whereby the electric motor supplies electrical power to the one or more supply lines.
In another aspect of the present invention, a method of momentarily sustaining power in one or more supply lines of an electrical thrust reverser system during an interruption of electrical power includes supplying electrical power from a power source, via the one or more supply lines, to an electric motor. The electric motor is coupled to one or more thrust reverser actuators, and is driven by the supply power to operate in a motoring mode. The electrical status of the power source is determined and, when the determined electrical status is that the power source is deenergized, operating the electric motor in a generating mode, whereby the motor supplies electrical power to the one or more supply lines.